/**
 * Copyright (C) 2008 Google Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.google.inject.internal;

import com.google.inject.internal.BytecodeGen.Visibility;
import com.google.inject.internal.InjectorImpl.MethodInvoker;
import com.google.inject.spi.InjectionPoint;

import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.lang.reflect.Modifier;

/**
 * Invokes an injectable method.
 */
final class SingleMethodInjector implements SingleMemberInjector {
    private final MethodInvoker methodInvoker;
    private final SingleParameterInjector<?>[] parameterInjectors;
    private final InjectionPoint injectionPoint;

    SingleMethodInjector(InjectorImpl injector, InjectionPoint injectionPoint, Errors errors) throws ErrorsException {
        this.injectionPoint = injectionPoint;
        final Method method = (Method) injectionPoint.getMember();
        methodInvoker = createMethodInvoker(method);
        parameterInjectors = injector.getParametersInjectors(injectionPoint.getDependencies(), errors);
    }

    private MethodInvoker createMethodInvoker(final Method method) {

        // We can't use FastMethod if the method is private.
        int modifiers = method.getModifiers();
        if (!Modifier.isPrivate(modifiers) && !Modifier.isProtected(modifiers)) {
            /*if[AOP]*/
            try {
                final net.sf.cglib.reflect.FastMethod fastMethod = BytecodeGen.newFastClass(method.getDeclaringClass(), Visibility.forMember(method)).getMethod(method);

                return new MethodInvoker() {
                    public Object invoke(Object target, Object... parameters) throws IllegalAccessException, InvocationTargetException {
                        return fastMethod.invoke(target, parameters);
                    }
                };
            } catch (net.sf.cglib.core.CodeGenerationException e) {
                /* fall-through */}
            /*end[AOP]*/
        }

        if (!Modifier.isPublic(modifiers) || !Modifier.isPublic(method.getDeclaringClass().getModifiers())) {
            method.setAccessible(true);
        }

        return new MethodInvoker() {
            public Object invoke(Object target, Object... parameters) throws IllegalAccessException, InvocationTargetException {
                return method.invoke(target, parameters);
            }
        };
    }

    public InjectionPoint getInjectionPoint() {
        return injectionPoint;
    }

    public void inject(Errors errors, InternalContext context, Object o) {
        Object[] parameters;
        try {
            parameters = SingleParameterInjector.getAll(errors, context, parameterInjectors);
        } catch (ErrorsException e) {
            errors.merge(e.getErrors());
            return;
        }

        try {
            methodInvoker.invoke(o, parameters);
        } catch (IllegalAccessException e) {
            throw new AssertionError(e); // a security manager is blocking us, we're hosed
        } catch (InvocationTargetException userException) {
            Throwable cause = userException.getCause() != null ? userException.getCause() : userException;
            errors.withSource(injectionPoint).errorInjectingMethod(cause);
        }
    }
}
